Mercurial > repos > ImageTools / file comparison
comparison: src/Translate.jl
src/Translate.jl
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- eef71dd7202b
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| 1 ###################################### | |
| 2 # Image subpixel accuracy translation | |
| 3 ###################################### | |
| 4 | |
| 5 module Translate | |
| 6 | |
| 7 ########## | |
| 8 # Exports | |
| 9 ########## | |
| 10 | |
| 11 export interpolate2d, | |
| 12 interpolate2d_quadrants, | |
| 13 extract_subimage!, | |
| 14 translate_image!, | |
| 15 DisplacementFull, | |
| 16 DisplacementConstant, | |
| 17 Displacement, | |
| 18 Image | |
| 19 | |
| 20 ################## | |
| 21 # Types | |
| 22 ################## | |
| 23 | |
| 24 # Two different types of displacement data supported: | |
| 25 # a) given in each pixel | |
| 26 # b) constant in space | |
| 27 Image = Array{Float64,2} | |
| 28 DisplacementFull = Array{Float64,3} | |
| 29 DisplacementConstant = Array{Float64,1} | |
| 30 Displacement = Union{DisplacementFull,DisplacementConstant} | |
| 31 | |
| 32 ############################# | |
| 33 # Base interpolation routine | |
| 34 ############################# | |
| 35 | |
| 36 @inline function interpolate2d_quadrants(v, (x, y)) | |
| 37 (m, n) = size(v) | |
| 38 clipx = xʹ -> max(1, min(xʹ, m)) | |
| 39 clipy = yʹ -> max(1, min(yʹ, n)) | |
| 40 | |
| 41 xfℤ = clipx(floor(Int, x)) | |
| 42 xcℤ = clipx(ceil(Int, x)) | |
| 43 yfℤ = clipy(floor(Int, y)) | |
| 44 ycℤ = clipy(ceil(Int, y)) | |
| 45 | |
| 46 xf = convert(Float64, xfℤ) | |
| 47 xc = convert(Float64, xcℤ) | |
| 48 yf = convert(Float64, yfℤ) | |
| 49 yc = convert(Float64, ycℤ) | |
| 50 xm = (xf+xc)/2 | |
| 51 ym = (yf+yc)/2 | |
| 52 | |
| 53 vff = @inbounds v[xfℤ, yfℤ] | |
| 54 vfc = @inbounds v[xfℤ, ycℤ] | |
| 55 vcf = @inbounds v[xcℤ, yfℤ] | |
| 56 vcc = @inbounds v[xcℤ, ycℤ] | |
| 57 vmm = (vff+vfc+vcf+vcc)/4 | |
| 58 | |
| 59 if xfℤ==xcℤ | |
| 60 if yfℤ==ycℤ | |
| 61 # Completely degenerate case | |
| 62 v = vmm | |
| 63 else | |
| 64 # Degenerate x | |
| 65 v = vff+(y-yf)/(yc-yf)*(vfc-vff) | |
| 66 end | |
| 67 elseif yfℤ==ycℤ | |
| 68 # Degenerate y | |
| 69 v = vff + (x-xf)/(xc-xf)*(vcf-vff) | |
| 70 elseif y-ym ≥ x-xm | |
| 71 # top-left half | |
| 72 if (y-ym) + (x-xm) ≥ 0 | |
| 73 # top quadrant | |
| 74 v = vfc + (x-xf)/(xc-xf)*(vcc-vfc) + (y-yc)/(ym-yc)*(vmm-(vcc+vfc)/2) | |
| 75 else | |
| 76 # left quadrant | |
| 77 v = vff + (y-yf)/(yc-yf)*(vfc-vff) + (x-xf)/(xm-xf)*(vmm-(vfc+vff)/2) | |
| 78 end | |
| 79 else | |
| 80 # bottom-left half | |
| 81 if (y-ym) + (x-xm) ≥ 0 | |
| 82 # right quadrant | |
| 83 v = vcf + (y-yf)/(yc-yf)*(vcc-vcf) + (x-xc)/(xm-xc)*(vmm-(vcc+vcf)/2) | |
| 84 else | |
| 85 # bottom quadrant | |
| 86 v = vff + (x-xf)/(xc-xf)*(vcf-vff) + (y-yf)/(ym-yf)*(vmm-(vcf+vff)/2) | |
| 87 end | |
| 88 end | |
| 89 | |
| 90 return v | |
| 91 end | |
| 92 | |
| 93 interpolate2d = interpolate2d_quadrants | |
| 94 | |
| 95 ############## | |
| 96 # Translation | |
| 97 ############## | |
| 98 | |
| 99 @polly function translate_image!(x, z, u::DisplacementFull) | |
| 100 @assert(size(u, 1)==2 && size(x)==size(u)[2:end] && size(x)==size(z)) | |
| 101 | |
| 102 @inbounds @simd for i=1:size(x, 1) | |
| 103 @simd for j=1:size(x, 2) | |
| 104 pt = (i - u[1, i, j], j - u[2, i, j]) | |
| 105 x[i, j] = interpolate2d(z, pt) | |
| 106 end | |
| 107 end | |
| 108 end | |
| 109 | |
| 110 @polly function translate_image!(x, z, u::DisplacementConstant) | |
| 111 @assert(size(u)==(2,) && size(x)==size(z)) | |
| 112 | |
| 113 @inbounds @simd for i=1:size(x, 1) | |
| 114 @simd for j=1:size(x, 2) | |
| 115 pt = (i - u[1], j - u[2]) | |
| 116 x[i, j] = interpolate2d(z, pt) | |
| 117 end | |
| 118 end | |
| 119 end | |
| 120 | |
| 121 ###################### | |
| 122 # Subimage extraction | |
| 123 ###################### | |
| 124 | |
| 125 @polly function extract_subimage!(b, im, v::DisplacementConstant) | |
| 126 (imx, imy) = size(im) | |
| 127 (bx, by) = size(b) | |
| 128 | |
| 129 # Translation from target to source coordinates | |
| 130 vxʹ = v[1] + (imx-bx)/2 | |
| 131 vyʹ = v[2] + (imy-by)/2 | |
| 132 | |
| 133 # Target image indices within source image | |
| 134 px = ceil(Int, max(1, vxʹ + 1) - vxʹ) | |
| 135 py = ceil(Int, max(1, vyʹ + 1) - vyʹ) | |
| 136 qx = floor(Int, min(imx, vxʹ + bx) - vxʹ) | |
| 137 qy = floor(Int, min(imy, vyʹ + by) - vyʹ) | |
| 138 | |
| 139 b .= 0 | |
| 140 | |
| 141 @inbounds @simd for i=px:qx | |
| 142 for j=py:qy | |
| 143 b[i, j] = interpolate2d(im, (i+vxʹ, j+vyʹ)) | |
| 144 end | |
| 145 end | |
| 146 end | |
| 147 | |
| 148 end |
